Long term is 10-12 years maybe a bit long. If an investor wants to withdraw profits and increase the amount of real assets within four years (one cycle), then it can be realistic for him . Instead of withdrawing his entire investment. If his profit amount in one cycle is more than he thought during the period of regular DCA method. For some reason, the possibility that the price of Bitcoin may fall should be considered in the investment thinking and you may be better off removing funds equal to the profit from the capital after a cycle.
Continuous DCA strategy and accumulation will continue and there is a strong desire to increase your assets from profits. I think selling Bitcoin before the completion of a four-year cycle is a trading mentality, so the long term should be 4-10 years.
I would imagine that some investors who have been in the market for less than 4 years can be considered new investors. It takes a long time to accumulate Bitcoin in particular. If you reach the excess savings level in the middle of 1 cycle, you can sell if you want. But you have not reached your savings target and you have made some money and you want to sell and take a profit, this is never a sign of an investor but a sign of a trader. It is not right to sell your holdings until the time limit or until you reach the excess savings.
Over accumulation or excess savings as you called it is not an issue, what's the issue is selling some part of your Bitcoin holdings when still in your accumulation stage, but if you have past that stage, you might decide to start taking profit from your holdings, and I believe that it's definitely going to take more than 10 years of consistent investment in Bitcoin to achieve such fit, what's not easy about it is staying discipline and focus in investing consistently for such a longer duration of time like 10 years or more, but what am trying to say is that wether you have gotten to that level of over accumulation or not, as long as you are still in your accumulation stage, selling or taking profit is never an option, it's something we should avoid doing by all means.
I know that we all look, but we see differently, so many people sees 4-8 years as long term, but in my own perspective, anything below 10 years interval is short term thinking, and the best way to milk the best possible dividend from your holdings is to hold for at least three circles or more, because that when you can get the best possible result from your holdings.